Crossword Genius

Unspecified philosophy or system of belief (3)

Ross

I believe the answer is:

ism

(Other definitions for ism that I've seen before include "Any ideological doctrine" , "Belief system" , "Informally, any doctrine or practice" , "Distinctive doctrine or practice" , "Informal noun or suffix for doctrine or practice" .)

I've seen this clue in The Times.
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